1. Field of the Invention
The present invention relates to medical apparatus and methods. More particularly, the present invent relates to urethral catheters and methods for introducing such catheters past the urinary sphincter.
Urethral drainage catheters, better known as Foley catheters, comprise a flexible tube that is passed through the urethra and into the bladder. The tube has two or more separated channels, or lumens, running down its length. One lumen is open at both ends, and allows urine to drain out into a collection bag. Another lumen, or side lumen, typically has a valve on the outside end and connects to a balloon at the tip. The balloon is inflated with sterile water or saline within the bladder just above the bladder neck to anchor the catheter in place.
While generally effective, long term placement of urethral drainage catheters is associated with a number of problems. In particular, urethral drainage catheters tend to become coated over time with a biofilm that obstructs the drainage path, requiring that the catheter be flushed or replaced. Replacement of the catheter requires that the catheter be advanced past the urinary sphincter, and repeated replacements can damage the sphincter and in some cases cause infection. The urinary sphincter is normally closed so that the catheter must physically open the sphincter each time it is replaced in order to reach the bladder.
For these reasons, it would be desirable to provide improved urethral drainage catheters and methods for their introduction past the urinary sphincter as they are advanced to the bladder. Any changes to conventional urethral drainage catheters and their introduction protocols should be minimal, and any cost differential should be more than offset by a reduction in trauma to the patients. At least some of these objectives will be met by the inventions described below.
2. Description of the Background Art
US 2014/0128766 describes a Foley catheter that has been modified to measure temperature in the bladder. US 2014/0249595; US 2014/0058284; US 2014/0058588; and US 2014/0309550 describe catheters and systems for assessing and controlling the urinary sphincter.